Recently, compact electronic apparatuses such as cellular phones, lap-top personal computers, digital cameras, PDAs (Personal Digital Assistance), electronic pocket diaries, etc. have remarkably progressed and developed. As the power source for a compact electronic apparatus, a primary cell such as an alkaline dry cell, a manganese dry cell, etc. and a secondary cell such as a nickel-cadmium storage cell, a nickel-hydrogen storage cell, a lithium-ion cell, etc. are used.
Such an electronic apparatus as described above is compact in size, and can be supplied with a certain amount of electricity irrespective of the arrangement and posture of the cell thereinside. Therefore, for example, a lap-top personal computer can be used while it is held by an arm and carried in this state, and a cellular phone or a digital camera can be used while it is roughly put in a chest pocket or a bag and carried around in this state. In this way, these electronic apparatuses can be used in all kinds of postures, in accordance with situations in which users use these apparatuses.
However, from the aspect of the efficiency of energy utilization, it can not be said that the primary cell or the secondary cell mounted on these electronic apparatuses is used efficiently. Now, researches and developments for an alternative fuel cell for replacing the above-described types of primary cells and secondary cells and for realizing a higher energy utilization efficiency are flourishing.
A fuel cell is for directly deriving an electric energy from a chemical energy by utilizing an electrochemical reaction between the fuel with oxygen in the air, and is regarded as a promising cell. However, in a fuel cell using a liquid fuel as the fuel, the fuel container for storing the fuel must be handled carefully. To be more specific, this type of fuel cell stores the fuel in a liquid state. Therefore, each time the posture of the fuel container for storing the fuel is changed, the fuel moves in the fuel container in a direction as gravitationally pulled. At this time, air bubbles may be included in the fuel in some case. In this case, since the fuel containing air bubbles flows out of the fuel container, the flux (amount of flux) of the fuel from the fuel container becomes unstable. As a result, the amount of supply of fuel to be supplied to an electricity generation module for generating electricity using the fuel stored in the fuel container becomes also unstable, causing a drop in the ability of generating electricity. Therefore, it is difficult to mount a fuel cell using a liquid fuel as the fuel on a portable compact electronic apparatus.
Hence, there is proposed a fuel container which can, irrespective of the posture of how it is held, stabilize the supply of fuel to the electricity generation module.
Specifically, Unexamined Japanese Patent Application KOKAI Publication No. 2001-93551 (particularly, the paragraphs nos. 0011 to 0019 and FIG. 1) discloses a fuel container having a liquid fuel osmosis member provided therein and also having a pore as an anti negative pressure mechanism formed at a predetermined position on the side surface of the container. While a negative pressure in the fuel container is adjusted by the air being introduced from the pore, the fuel osmosing into the liquid fuel osmosis member is supplied from the fuel container to a stack which is the electricity generation module, due to capillary attraction.
According to the fuel container disclosed in the above-indicated publication, the fuel securely contacts and osmoses into the liquid fuel osmosis member irrespective of the posture of how the fuel container is held. Therefore, the fuel flows out from the fuel container with no air bubbles contained therein, making it possible to stabilize the supply of the fuel to the electricity generation module. However, when the amount of the stored fuel becomes small, the fuel remaining in the fuel container does not contact and osmose into the liquid fuel osmosis member if the fuel container is laid or held obliquely. Due to this, not all the stored fuel can be let out from the fuel container. That is, the fuel container disclosed in the above-indicated publication can stabilize the flow-out of the fuel from the fuel container irrespective of its posture, but leaves some of the fuel therein depending on its posture.